Stay out of MY yard!

A while back I went out with Seamus into the yard. He was put his nose up in the air and was gone after some great smell. I didn't think much of it until I heard a great scuffle. There are some places I can't see him, so I went to take a look. What do you see in this photo?

Notice the grey and white kitty in the tree above Seamus' head? She is our neighbors, and she stayed up there for about an hour until the coast was clear. I was a little bit mean and stayed outside on purpose for a while. Perhaps she will stay on her own side of the fence from now on?